Federal authorities are warning hotels in major U.S. cities to be vigilant after intelligence recently obtained in Somalia shows Al Qaeda was planning to launch a “Mumbai-style” attack on an upscale hotel in London, England, Fox News has learned exclusively.

The intelligence came from computer accessories and other materials gathered at the checkpoint in Mogadishu where Fazul Abdullah Mohammed, the Al Qaeda operative who masterminded the 1998 U.S. embassy bombings in East Africa, was killed Saturday, according to sources.

Al Qaeda was working on what one senior U.S. intelligence official described as an “aspirational” – but possibly operational – plot to target the Ritz Carlton hotel in London. As part of the plot, operatives would stay in strategically chosen rooms on the first floor of the hotel, and then they would set their rooms ablaze in hopes of trapping guests on the floors above.

The senior intelligence official said authorities have a "duty to inform" the hotel industry and others about potential threats.

In November 2008, 10 gunmen launched a raid on hotels and cafes in Mumbai, India's financial capital. The attack spanned three days, killing 174 people and wounding more than 300 others.